It has been found as a result of careful observation that, with one or two doubtful exceptions, the spectrum of a solid or liquid is always continuous; and within recent years attempts have been made successfully to express in mathematical form the connection between the temperature of the solid and the distribution of energy in its spectrum as a function of its wave-length. These laws have been deduced theoretically and verified by experiment. It has been found further that the spectrum of a gas when rendered luminous is in all cases discontinuous, although occasionally there is a faint continuous background. This fact in regard to gaseous spectra is what would be expected from the kinetic theory. The exact origin of the spectrum is in general inside the atom; but the connection between the parts of the atom and the ether in which waves are produced is not known. The spectra of compounds when rendered luminous at a temperature not sufficient to decompose definitely the substance have been studied with care, and many interesting facts have been discovered. It has been shown that all gases will produce under varying conditions different spectra, but the reason for this is by no means clear. There are at least three different spectra of hydrogen, many of oxygen, many of argon, etc. The influence of pressure, of temperature, and of the electrical conditions is marked; and these subjects form at present one of the most important fields of research in spectroscopy. The spectrum of a gas is modified if the source of light is either approaching or receding from the spectroscope, as, for instance, in the case of a star with a motion toward or away from the earth. It is owing to this fact that one is able, by a comparison of the spectra of certain stars with spectra produced here on the earth, to calculate the motion of the stars in the line of sight. See DOPPLER'S PRINCIPLE.

A careful comparison of the lines in the spectrum of any one gas or vapor, and of the spectra of different vapors, has led to the discovery of several simple mathematical laws connecting them. Thus the lines in the ordinary hydrogen spectrum have such wave-lengths that they can be expressed in a mathematical formula which is known as Balmer's law. This can be expressed as follows: λ=h where represents the ma 4 wave-lengths, m has in succession the values 3, 4, 5, etc., and h is a constant whose value is approximately 3647.20.

m2

A relation similar to this of Balmer's has been shown by Kayser and Runge to apply to most of the lines in the spectra of the alkalies and the alkaline earths. Another law has been found to express most accurately the distribution of the lines in the well-known bands which are produced by carbon, nitrogen, and other substances. Laws have been found also connecting the spectra produced by different substances, in those cases where these substances are related chemically.

In the year 1896 Zeeman discovered that a source of light if placed in a magnetic field and viewed either along the lines of force or at right angles to them had its spectrum changed by the resolution of its lines into several components. This fact has a most important bearing upon theories of matter and serves to prove that the

VOL. XVIII.-28.

SPECTROSCOPY.

vibrations in the ether are produced by the vibrations inside the atom of minute electrical charges which have been called electrons, A recent investigation of the Zeeman effect by Runge has shown that the components of these spectrum lines produced by the magnetic field also obey certain mathematical laws.

A most important branch of spectroscopy is the study of the solar spectrum as we observe it on the earth. A few of the absorption lines are due to the fact that the waves coming from the sun pass through the atmosphere of the earth, and, therefore, suffer absorption owing to the water vapor and oxygen in it. The 'rain band' is due to the presence of the former. The other lines are, as explained above, caused by the absorption in the atmosphere of the sun itself. The interior portion of the sun, which is at a high temperature, emits a continuous spectrum, but, owing to the presence in the atmosphere of the sun of metallic vapors at a temperature less than that of the interior, there is absorption, and thus the solar spectrum is a continuous one crossed by dark lines. There are radiations also coming to us from the outer portions of the sun, the socalled chromosphere and corona; but these are not easily observed, except at times of solar eclipses. Most of the solar lines can be identified with the spectra of known substances on the earth; for instance, sodium, iron, carbon, etc., are known to be in the sun. It may be stated in general that if the earth were raised to a temperature as high as that of the sun its spectrum as seen at a distance would be practically identical with that of the sun as we see it.

A careful study has been made of the spectra of the various stars, and attempts have been made with more or less success to group the stars in certain classes according to their spectra, the idea being that some knowledge might be obtained in regard to the evolution of the stars and Schuster, "The Evolution of Solar Stars," Astrotheir present stage in this progress. Consult physical Journal, April, 1893.

Fraunhofer lines in the solar spectrum, as measThe wave-lengths of a few of the important ured by Professor Rowland, are as follows:

BIBLIOGRAPHY. There is a complete discussion of the methods, results, and theories of spectroscopy in Kayser, Lehrbuch der Spektroskopie (Leipzig, 1900). A briefer account is given in Landauer, Spectrum Analysis (New York, 1897). Fraunhofer's original papers are reprinted in Prismatic and Diffraction Spectra, Scientific Memoir Series, vol. ii. (New York, 1898); and those of Stewart and Kirchhoff in Radiation and Absorption, same series, vol. xv. (New York, 1901). Rowland papers On Concave Gratings for Optical Purposes (1883); On the Relative Wave Lengths at the Lines of the Solar Spectrum (1886); together with other papers contained in his collected physical papers (Baltimore, 1902), should be consulted by the student. More popular books dealing with spectroscopy are: Lockyer, Contributions to Solar Physics (London, 1874); id., Chemistry of the Sun (Lon

don, 1877); Roscoe, Spectrum Analysis (London, 1866); Schellen, Spectrum Analysis (New York, 1872). See LIGHT.

SPECTRUM. See LIGHT; DISPERSION; SPECTROSCOPE; SPECTROSCOPY.

SPECTRUM ANALYSIS. As is explained in the article on SPECTROSCOPY, the spectrum of a definite substance under definite conditions is always the same. The spectrum of the radiations emitted by iron vapor, for instance, when rendered luminous, is characterized by certain definite trains of waves, or, as ordinarily expressed, by certain lines.' If the conditions under which the spectra are produced are varied, for instance, if for one case the spark was used, and in another the arc, there are differences in the spectra, consisting mainly in variations in the intensity of the lines. Further, if other substances are mixed with the iron, or if the iron exists as an impurity in some other substance, or if the pressure of the surrounding atmosphere is varied, there are corresponding alterations in the iron spectrum. But under definite conditions there are definite lines which are characteristic of iron. Extremely small traces of a substance may be thus made evident by the presence of its spectrum; and in a mixture of many substances the presence of the various parts may often be ascertained by a study of the spectrum emitted. This constitutes the science of spectrum analysis and has proved useful to the chemist in many cases. In fact the discovery of several elements, viz. cæsium, rubidium, and gallium, was due to the detection in certain spectra of lines which could not be ascribed to any known substances. The application of spectrum analysis to the study of the spectra of the sun, stars, and other heavenly bodies has proved most important, and some of the results of various observations and investigations are given in the article on SPECTROSCOPY (q.v.).

SPECULAR IRON ORE. See HEMATITE. SPECULATION (Lat. speculatio, exploration, contemplation, from speculari, to view, watch, spy out, from specula, watch-tower, from specere, to see). Buying and selling of property chiefly with a view to securing a profit through changes in the price of that property. There is a speculative element in a great variety of business transactions; but the term is usually confined to those in which the element of risk is relatively important.. In former times speculative activity was largely engaged in seeking to take advantage of differences in price in distant markets. Foreign trade 100 years ago was highly speculative. Improvements in transportation and in means of communication have reduced such differences to a matter of exact calculation. Speculative business has, therefore, come to be confined almost exclusively to transactions involving the time element.

In its simplest form time speculation involved the buying of property outright, and the holding of it in anticipation of a rise in price. This practice is as old as civilization, and until late times has usually been regarded as socially injurious. Toward the end of the seventeenth century the practice developed in Holland of buying and selling the products of fishing voy ages before the results of the voyage were actually known. In the early part of the eighteenth

century speculation in grain, coffee, etc., was very active in Amsterdam, developing many of the practices of modern exchanges. In all of these early forms of speculation, however, what was bought and sold was the right to a particular lot of goods.

When

With the development of warrants and the grading of goods speculation received a new impetus. It thus became possible for a man to sell goods which he did not possess, since he could at any time secure identical goods upon the market if he could pay the price. It is largely to this principle that the phenomenal development of speculation in recent years is due. For the extent of speculative dealings and the practices of modern exchanges, see STOCK EXCHANGE. ECONOMIC FUNCTION OF SPECULATION. the supply of any commodity is subject to great uncertainty, as, for example, the products of agriculture, it is manifestly to the advantage of society that it should be properly distributed through a period of considerable length. A class of individuals who study the conditions of demand and supply endeavoring to buy such commodities when they are abundant and cheap, in order to sell them when they are dear, serve to bring about such a distribution of consumption and thus render an important social service. Again, some commodities, such as iron, are subject to great fluctuations in demand, and hence in price, thus introducing a large element of uncertainty into all of those forms of industry which make extensive use of them. The speculator, by making contracts to deliver the article at a future date at a fixed price, frees the consumer from that uncertainty. Legitimate speculation thus serves as a means of insurance against certain classes of risks.

It may be, however, that the speculator is mistaken in his estimates of future supply and demand. In that case he exaggerates the evil which it is his function to minimize. Thus speculation may keep prices abnormally high for a period, only to render prices abnormally low for a succeeding period. Speculation may thus bring about a crisis (q.v.) with its attendant industrial stagnation.

A more serious evil results from the fact that speculation is carried on not only by those who are conversant with market conditions, but by a large class of individuals who engage in it without the proper equipment of technical knowledge. Unscrupulous operators, through false reports, or through their own apparent eagerness to buy or sell, often lead such unsophisticated speculators to their financial ruin. Such influences tend to increase business uncertainty, and hence diminish considerably the net social gain from speculation.

Popular sentiment in England and America has generally been hostile to speculation, and laws have frequently been passed to prevent it. An act of Parliament was passed in 1733, “To prevent the infamous practice of stock-jobbing." The act had no effect and was repealed in 1860. In America an act was passed in 1864 to prevent speculation in gold, but its operation was so unsatisfactory that it was repealed in two weeks. In several of the States laws have been enacted aiming to prohibit speculation in one form or another. These have proved quite ineffective. Bills were introduced in the Fiftyfirst, Fifty-second, and Fifty-third Congresses

SPECULATION.

which were designed to prevent certain forms of speculation in grain, but did not become law. Consult: Emery, Speculation on the Stock and Produce Exchanges of the United States (New York, 1896); Hadley, Economics, chapter "Speculation" (ib., 1898). See also general treatises on political economy (q.v. for references).

SPED DING, JAMES (1808-81). An editor of Bacon's works. He was born in Cumberland, England. From the grammar school at Bury Saint Edmunds he passed to Trinity College, Cambridge, where he graduated in 1831. Leaving Cambridge in 1835, he entered the Colonial Office. This position he gave up in 1841 that he might devote himself to the study of Bacon. For 30 years he continued his researches with slight interruptions. He died from an accident in London. Spedding's most delightful book is Evenings with a Reviewer (written in 1845, and privately printed; published 1881), in which with quiet humor Macaulay's essay on Bacon is torn into shreds. His magnum opus is an edition of Bacon's entire works with an exhaustive life (14 vols., 1857-74), in the preparation of which he was in some degree aided by Leslie Ellis and D. D. Heath. The biographical and historical parts of this work, much cut, were published under the title, Account of the Life and Times of Bacon (2 vols., 1878). Spedding in English History (1881) and wrote several other admirable historical papers. Consult the memoir of G. S. Venables prefixed to Evenings with a Reviewer (London, 1881); Edward Fitzgerald's Letters (ib., 1889); and Hallam Lord Tennyson's Memoir of his father (London and New York, 1897).

also contributed articles to J. Gairdner's Studies

SPEECH (AS. spæc, spēc, spræc, sprēc, OHG. sprahha, Ger. Sprache, speech, from AS. specan, sprecan, OHG, sprehhan, Ger. sprechen, to speak; possibly connected with Skt. sphūrį, to murmur). The act of producing vocal sound for the communication of ideas. Speech differs from voice in that the latter is rather the physiological potentiality and mechanical process, and from vocal language, which is the result produced by speech. Speech is, so far as known, like vocal language, peculiar to man, although attempts have been made to assign it also to monkeys and apes, while gesture language (q.v.) is shared by man with other animals. In a looser sense speech is synonymous with language. See LAN

GUAGE; VOICE.

SPEED, JAMES (1812-87). An American politician, born near Louisville, in Jefferson County, Ky. He graduated at Saint Joseph's College (Bardstown), was in the office of the clerk of the Circuit and County Courts, and after further legal study at Transylvania University began practice at Louisville in 1833. In 1847 he was elected to the State Legislature, where he served one term. He was the most effective opponent of the disunion cause in Kentucky, was elected to the State Senate in 1861, and in 186164 was in charge of the Kentucky recruiting stations. In 1864 he was appointed AttorneyGeneral of the United States by President Lincoln, but he resigned from the post in 1866 because of his opposition to the reconstruction

policy of President Johnson. In 1856-58 and 1875-79 he held a chair in the law department of the University of Louisville. His reputation as a jurist was considerable.

SPEED, JOHN (c.1552-1629). An historical antiquary, the son of a London tailor. Through the generosity of Lord Brooke, he was able to give up manual labor and devote himself to study. Between 1600 and 1610 he published 54 maps of England and Wales, which were collected and described under the title of Theatre of the Empire of Great Britaine (1611). He next published the great work on which he had been engaged for many years: The History of Great Britaine, from the invasion of Julius Cæsar to King James I. (1611). This is regarded as the best history up to that time written by an Englishman. He also published Genealogies Recorded in Sacred Scripture (about 1611), of which 33 editions appeared in the course of 30 years, some of them being attached to issues of the Bible, and A Cloud of Witnesses Confirming the Holie Word (1616).

SPEEDWELL (Veronica). A genus of about 200 annual and perennial herbs and shrubs of the natural order Scrophulariaceæ, natives of in ditches and marshes, some only on the driest temperate and cold climates. Some species grow soils. They have generally very beautiful blue, white, or pink flowers, for which several species are cultivated. The bitter and astringent leaves widely distributed in the Northern Hemisphere, of the common speedwell (Veronica_officinalis), are in some countries used medicinally and as a substitute for tea, as are those of the germander speedwell. Veronica Virginica is called Culver's physic in North America. Brooklime (q.v.) belongs to this genus.

A

SPEISS (Ger. Speise, amalgam, food, OHG. spisa, food, from Olt., ML. spesa, expense, cost, from Olt. spendere, from Lat. expendere, to expend, from ex, out + pendere, to weigh). mixture of the antimonides, arsenides, and sulphides of copper, iron, and nickel, that collects at the bottom of a crucible when ores of arsenic, antimony, cobalt, or lead, containing sulphur, are smelted with fluxes. The speiss containing nickel, which is obtained largely in the preparation of smalt, is an important source of that metal.

SPEKE, spēk, JOHN HANNING (1827-64). An English African explorer. He was born at Jordans, Somersetshire, entered the Indian army in 1844, served in the Punjab campaigns, and distinguished himself as a soldier, naturalist, and sportsman. While in the Indian service he made several trips into the Himalayas and even entered Tibet, bringing back valuable collections. He began his brilliant though brief career as an African explorer in 1854, when he accompanied Captain Burton into Somaliland. He was also Burton's companion on the expedition of 1857-59 from Zanzibar into the interior of Africa. 1858 they discovered Lake Tanganyika, and in the same year, while Burton was ill at Kaze, Speke reached the Victoria Nyanza. He believed that he had found one of the sources of the Nile, but Burton discredited the information he brought back and Speke could not verify his discovery until 1862, when he returned to the lake with Capt. J. A. Grant, and, proceeding northward, came to the Nile, which he found to be the

In